Safety leg for elevators



De' 12, 1933 L.. c. sTuKENBoRG SAFETY LEG FOR ELEVATORS Filed Aug. 26, 1951 /6 ldd/a C. 6pm-www Patented Dec. 12, 1933 UNITI-:D STATES PATENT OFFICE sAFETYLl-:G Foa ELnvA'Tons Y C. Stukenborg, Memphis, Tenn. Application August 26, 1931. serial No. 559,368

9 Claims. (o1. 254-93) This invention relates to a leg or support .for holding an elevator or lift in raised position until purposely released whereby a safety support is furnished against accidental falling. 1n vehicle lifts of the hydraulic or air actuated type it often happens that a broken connection or other `cause allows the lift to drop endangering both life and property. The same thing is `true also of elevators not only of the hydraulic type but of that type which areraisedby cables in which latter especially safety devices of numerous types are installed to prevent .accidental falling because of cable breakage or other failureof apparatus to act.

The object of the .present invention is'to provide a safety leg which will automatically follow the raising of an elevator or lift and support same in any position of the .device .and which must Ybe manually released to permit .lowering of the elevator. I

The means by which the foregoing and other Gblects areaccomplishedand the manner of their accomplishment will readily be vunderstood from the following specification on reference to the accompanying drawing,`inwhich:

lFig. l'is a sectional elevation on the 'center line of the plunger. of a hydraulic lift showing the device .equipped with duplicate safety legs;

l Fig. 2 is .a perspectiveview of a rotary automobile lift .structure of 'the free wheel type provided with my improved safetyl legs; and

Fig. 3 is an enlarged fragmentary view showing a check and release valve for the` safety leg.

Referring now to the drawing in which the varl- Y ous parts are indicated bylnumerals, 10 is avertical cylinder having its top substantially flush with the .surface of the ground in which cylinder isa verticallymovable plunger 11, to which is secured a `circular head `12 Von which is rotatably disposed a casting 13, to which rails 14 are secured.' 15 is a pipe through which oil or other liquid is supplied to the cylinder .10 from a tank 16 as by means of air supplied .through a .pipe 17 .from asource of .supply not shown, and not specifically here set out since the raising means is not stumng box in which suitableupacking 22-is held Y vThe valve opens automatically to ,permit transfer of the liquid from the plunger into the cylinder during upward movement of the plunger. The plunger in such event forming a reservoir from Y which liquid is supplied to the cylinder to hold the plunger against downward movement. The valve 25 is provided with .a stem 28, which extends upward beyond the top of the cylinder .andi through the head 12 and which may be depressed, as by .the rocker arm 29, to .move the valve 25 from its .seat and allow return flow to the plunger. It will be noted that no stulng box is 'provided for the upper end of this stem, thus permitting ingress of air to, and egress from, the Ireservoir 84) in said plunger and establishing communicationY between said reservoir and the atmosphere. In the illustrated type in which the casting 113, is rotatable with respect to the head 12 the vinner end of the rocker arm 29 rests on a disc 30 'from ,85 whichy a centrally disposed pin 3l projects upward through the casting 13 and thereabove is engaged by a lever 32 integral with a rod 33. AThe rod 33 is provided with a handle 34 accessible to an nattendant for thepurpose of depressing the stem 28 and valve 25 to permit return flow of the liquid from the cylinder to the plunger.

A vehicle lift of this particular type may be provided with one or even Vmore of the safety legs, two, as before stated, being here shown. Ordinarily the size of the plunger is much less than` that of the raising plunger with which it is to 'be associated since leg pressures are static whereas elevator raising plunger pressures are working pressures.

In using the device the lift plunger 11 is'actuated in usual manner thus raising the head'and other appurtenances carried thereby. As the `head rises it carries up with it the safety leg plunger or plungers as the case may be causing the liquid within the plunger to flow past the valve 25 to the cylinder 18 thereby at all times keeping the cylinder Vfull of liquid. On cessation of upward movement from any cause whatsoeventhe valve 25 automatically seats thereby establishing below 110 the plunger 19 a closed chamber for the liquid and preventing return movement of the plunger, thus automatically establishing a safety support or leg beneath the elevator table or cage.

It will be noted that this leg acts at any and all positions of rise of the lift so that it is only necessary for the support to carry the actual load without provision for impact, since action of the support iscoincident with the need thereof. At any time that it is desired to lower the lift the valve may be opened to establish return flow -to theV plunger and lowering accomplished as though no leg were provided, with the safeguard however that safety action may be invokedon the downward movement at any time by release of the valve controls, Y

It will readily be understood that a hydraulic elevator may be identically lequipped since such elevator is merely a lift of greater range than that here shown.

It will also be readily seen that'an identical leg may be placed beneath any elevator cage no matter by what means the same may be raised.

It will vbe readily understood therefore that while the device has been shown as applied to a vehicle lift it is equally applicable to any type of elevator andthat in the claims the use of the term elevator specifically covers vehicle lifts as well as other types of elevators.

j It will also be understood that the liquid supply may be led to the cylinder from other reservoir than the plunger without departing from my invention.

' Having described my invention, what I claim isz- '1. In mechanism of the class described, havr ing raising and lowering means, a safety device, ,comprising a plurality of vertically disposed'hollow cylinders, a hollow plunger vertically slid- `able withineach cylinder, saidlplunger having a head closing its lower end, and its upper end open to the atmosphere, a supply of liquid in said plungersand cylinders, means on the head permitting flow from the plunger to the vcylinlder and preventing return flow to the plunger,

"and manually controlled means for concurrently establishing return flow in all of said cylinders,

veach plunger jextending above its cylinder and being secured to said elevatol` and movable therewith and thereby, whereby transferl of liquid from said 'plungers to said cylinders'to support saidv elevator independently of said raising and lowering means, is accomplishedby the raising vof ,said elevator, and such support is maintained ing raising and lowering means, a safety device,

comprising a plurality of vertically disposed hollow cylinder`s, a hollowplunger vertically slidable within each cylinder, said plunger having the cylinder and preventing return Ilow to the plunger, and manually controlled means for establishing return ilow concurrently in all of said cylinders, each plunger extending above its cylinder and being secured to said elevator, whereby transfer of liquid from said plungers to said cylinders to support said elevator independentlyof said raising andlowering means, is accomplished by the raising vof said elevatonand lowering thereof may be controlled by said means for establishing'return ilow.

3. In mechanism of the class described, having raising and lowering means, a safety device, comprising a plurality of vertically disposed hollow cylinders, a hollow plunger vertically slidable within each cylinder, said plunger having a head closing its lower end, and itsupper end opento the atmosphere, a supply of liquid in said plungers and cylinders, a valve carried by the head permitting flow from the plunger to the cylinder and preventing return flow to the plunger, and manually controlled means for rendering all of said valves concurrently ineffective, to allow return ilow, eachv plunger extending above'its cylinder and being secured to said elevator, whereby transfer of liquid from said plungers to Ysaid cylinders to support said elevator independently of said raising and lowering means, is accomplished by the raising of said elevator, and lowering thereof may be regulated by said manually controlled means.

4. In mechanism of the class described, having raising and lowering means, a safety device comprising a plurality of vertically disposed hollow cylinders, vertically movable hollow plungers one in each of said cylinders, said plungers extending above said cylinders and being secured to the underside of said elevator and mov- `able thereby and therewith, said plungers each having a head closing its lower end, and its upper end open to the atmosphere, said cylinders and plungers being of length suiiicient to allow the full travel of said elevator, supplies of liquid at all times under atmospheric pressure lling each of said cylinders and plungers, check valves one in each of said heads, each permitting ow from `a plunger to its cylinder and preventing return flow, and manually controlled means for concurrent opening ofr all of said valves to allow' return flow at the same time from all of said cylindersfto their respective plungers, whereby lowering of said elevator when unsupported by said raising and lowering means, is permitted upon concurrent opening of a. plurality of said valves.

5. In combination with an elevator having raising and lowering means, a safety device compris- Ying a vertically disposed hollow cylinder, a holl low plunger vertically slidable therein, said plunger extending above said cylinder and being secured to said elevator, and movable therewith and thereby, and having a head closing its lower end, and its upper end open to the atmosphere, a

supply of liquid in said plunger and cylinder, af

valve carried by said head and normally permitting flow from said plunger to said cylinder while preventing return flow to said plunger, andA manually controlled means operable upon said valve for establishing such return flow either when said" elevator is in its uppermost position or at any stage of its downward movement, whereby such downward movement may be either checked or permitted to continue at any raised position of the elevator, when it is unsupported by said rais-` ing and lowering means, rby operation of said valve-control means.

6. In combination with an elevator having raising and lowering means, a safety device comprising a verticallydisposed hollow cylinder, a :if

hollow plunger vertically slidable therein, said plunger extending above said cylinder and being secured to said elevator,and movable therewith and thereby, and having a head closing its lower end, and its upper end open'to the atmosphere,

a supply of liquid in said plunger and cylinder, a valve carried by said head and normally permitting ow from said plunger to said cylinder while preventing return flow to said plunger, whereby in the absence of support by said raising and lowering means said elevator is supported by the liquid in said cylinder, and manually controlled means for establishing and regulating return flow to said plunger to permit and control downward movement.

7. The combination with an elevator having raising and lowering means, and manually operable means for the control thereof, of a safety. device comprising a vertically disposed hollow' cylinder, a hollowplunger vertically slidable therein, said plunger extending above said cylinder and being secured to said elevator and movable therewith and thereby, said plunger having a head closing its lower end, and its upper end open to the atmosphere, a supply of liquid in said plunger and cylinder, a valve carried by said head and normally permitting now from said plunger to said cylinder while preventing return ow to said plunger, and manually controlled means independent of said first-named control means, for permitting and regulating such return flow at any stage in the downward movement of said elevator, when said elevator is unsupported by said raising and lowering means, whereby two separate and individually controlled means are provided for holding said elevator against downward movement or regulating such movement.

8. In combination with an elevator having raising and lowering means, a safety device comprising a vertically-disposed hollow cylinder; a plunger vertically slidable therein; a source of liquid supply for said cylinder, said plunger extending above said cylinder and being secured 'to said elevator, and being movable therewith and thereby, whereby upon upward movement thereof such liquid is drawn into said cylinder by said plunger; a valve normally permitting flow of liquid to said cylinder, while preventing return ilow therefrom, whereby in the absence of support by said raising and lowering means, said elevator is supported by the liquid in said cylinder; and manually-operable means for establishing and regulating liquid iiow from said cylinder, to permit and control-downward move- Vment of said elevator when unsupported by said raising and lowering means.

9. In combination with an elevator lhaving raising and lowering means, a safety device employing liquid as a support medium, and comprising a plurality of vertically-disposed hollow cylinders; plungers, one for each of said cylinders; each plunger extending above its cylinder and being secured to said elevator, and being movable therewith and thereby, whereby upon upward movement thereof liquid is drawn into said cylinders by their plungers; valves, one for each cylinder, normally permitting now of liquid to the cylinder,v while preventing returnA flow therefrom, whereby in the absence of support by said raising and lowering means, said elevator is supported by the liquid in said cylinders; and manually-operable means for concurrently establishing and regulating liquid ilow from said cylinders, to permit and control downward movement of said elevator when unsupported by said raising and lowering means.

LOUIS C. STUKENBORG. 

